If you stop working out, how long before you start to lose muscle gains?

Fellas, I injured my back yesterday and seeing the doctor tomorrow. I'm pretty sure the doc will tell me to back off the weight lifting exercises for a couple of weeks if not more. My question is, how can I best retain the muscle I've gained without working out for this period of time?

Anyone have any ideas? Don't have much in terms of reps but will rep of course...thanks...

well I haven't worked out in about 6 months well upper body anyway since I dislocated my shoulder and I lost about 20lbs of muscle but I will be getting surgery soon and that will be another 6 months til I get back in the gym.

I noticed around the 2nd week I began to lose size but I think that was due to depression considering I was extermely depressed about hurting my shoulder and not working out

Eat clean stick and with your diet

My advice don't let your injury make you depressed!! If you have to take a few weeks off its not bad it will pass in a blink of an eye and once you get back in the gym you'll get back everything quicker than before because of muscle memory